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Granulometric study of placer sands across a multi-berm beach at Chavara, southwest coast of India

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Title Granulometric study of placer sands across a multi-berm beach at Chavara, southwest coast of India
 
Creator Unnikrishnan, E
Dinesh, A C
Nambiar, A R
Gangadharan, A V
 
Description 295-304
Heavy mineral bearing
beach sediments collected along a shore perpendicular transect between the surf
zone and monsoonal berm at Chavara were analyzed for their grain size
distribution of heavy mineral constituents. The principal

heavy
mineral present in this beach are
ilmenite (35- 64%), zircon (2-17%) sillimanite (4-9%), rutile (2-11%), monazite (1- 2%) and
leucoxene (1-2%). The heavy mineral content increases towards onshore in the
upper and lower foreshore slope, but the grain size becomes finer and better
sorted. Higher concentration of heavy mineral was found in the berms and upper
foreshore slope. The concentration factor of heavy minerals correlates well
with the specific gravity and the mean sizes suggesting that these parameters
play major roles in their selective sorting and concentration in the upper
foreshore slope.

The heavy mineral concentrates
so formed are carried to the foreshore berm as the water level rises during
high tide and are left behind as the water recedes. The transport paths of
heavy minerals determined from sediment trend matrix suggest that they move
differently from light minerals in the beach environment and the heavy minerals
are selectively deposited at the berms and upper part of the lower foreshore
slope. The geological set-up of the study area, and mineralogy and texture of
the constituent minerals, suggest that these heavy mineral placers are formed
mainly from the palaeo-beach deposits reworked and transported by the waves
during the Holocene sea level rise. The present day seasonal erosion of the
heavy mineral rich barrier beach system has further concentrated the heavy
minerals on the beach.
 
Date 2014-01-13T05:10:02Z
2014-01-13T05:10:02Z
2000-12
 
Type Article
 
Identifier 0975-1033 (Online); 0379-5136 (Print)
http://hdl.handle.net/123456789/25492
 
Language en_US
 
Rights CC Attribution-Noncommercial-No Derivative Works 2.5 India
 
Publisher NISCAIR-CSIR, India
 
Source IJMS Vol.29(4) [December 2000]